<?php
/*
* Copyright 2016 Google LLC
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
namespace Google\ApiCore;
use Generator;
use IteratorAggregate;
/**
* Response object for paged results from a list API method
*
* The PagedListResponse object is returned by API methods that implement
* pagination, and makes it easier to access multiple pages of results
* without having to manually manipulate page tokens. Pages are retrieved
* lazily, with additional API calls being made as additional results
* are required.
*
* The list elements can be accessed in the following ways:
* - As a single iterable used in a foreach loop or via the getIterator method
* - As pages of elements, using the getPage and iteratePages methods
* - As fixed size collections of elements, using the
* getFixedSizeCollection and iterateFixedSizeCollections methods
*
* Example of using PagedListResponse as an iterator:
* ```
* $pagedListResponse = $client->getList(...);
* foreach ($pagedListResponse as $element) {
* // doSomethingWith($element);
* }
* ```
*
* Example of iterating over each page of elements:
* ```
* $pagedListResponse = $client->getList(...);
* foreach ($pagedListResponse->iteratePages() as $page) {
* foreach ($page as $element) {
* // doSomethingWith($element);
* }
* }
* ```
*
* Example of accessing the current page, and manually iterating
* over pages:
* ```
* $pagedListResponse = $client->getList(...);
* $page = $pagedListResponse->getPage();
* // doSomethingWith($page);
* while ($page->hasNextPage()) {
* $page = $page->getNextPage();
* // doSomethingWith($page);
* }
* ```
*/
class PagedListResponse implements IteratorAggregate
{
private $firstPage;
/**
* PagedListResponse constructor.
*
* @param Page $firstPage A page containing response details.
*/
public function __construct(
Page $firstPage
) {
$this->firstPage = $firstPage;
}
/**
* Returns an iterator over the full list of elements. If the
* API response contains a (non-empty) next page token, then
* the PagedListResponse object will make calls to the underlying
* API to retrieve additional elements as required.
*
* NOTE: The result of this method is the same as getIterator().
* Prefer using getIterator(), or iterate directly on the
* PagedListResponse object.
*
* @return Generator
* @throws ValidationException
*/
public function iterateAllElements()
{
return $this->getIterator();
}
/**
* Returns an iterator over the full list of elements. If the
* API response contains a (non-empty) next page token, then
* the PagedListResponse object will make calls to the underlying
* API to retrieve additional elements as required.
*
* @return Generator
* @throws ValidationException
*/
public function getIterator()
{
foreach ($this->iteratePages() as $page) {
foreach ($page as $key => $element) {
yield $key => $element;
}
}
}
/**
* Return the current page of results.
*
* @return Page
*/
public function getPage()
{
return $this->firstPage;
}
/**
* Returns an iterator over pages of results. The pages are
* retrieved lazily from the underlying API.
*
* @return Page[]
* @throws ValidationException
*/
public function iteratePages()
{
return $this->getPage()->iteratePages();
}
/**
* Returns a collection of elements with a fixed size set by
* the collectionSize parameter. The collection will only contain
* fewer than collectionSize elements if there are no more
* pages to be retrieved from the server.
*
* NOTE: it is an error to call this method if an optional parameter
* to set the page size is not supported or has not been set in the
* original API call. It is also an error if the collectionSize parameter
* is less than the page size that has been set.
*
* @param $collectionSize int
* @throws ValidationException if a FixedSizeCollection of the specified size cannot be constructed
* @return FixedSizeCollection
*/
public function expandToFixedSizeCollection($collectionSize)
{
return $this->getPage()->expandToFixedSizeCollection($collectionSize);
}
/**
* Returns an iterator over fixed size collections of results.
* The collections are retrieved lazily from the underlying API.
*
* Each collection will have collectionSize elements, with the
* exception of the final collection which may contain fewer
* elements.
*
* NOTE: it is an error to call this method if an optional parameter
* to set the page size is not supported or has not been set in the
* original API call. It is also an error if the collectionSize parameter
* is less than the page size that has been set.
*
* @param $collectionSize int
* @throws ValidationException if a FixedSizeCollection of the specified size cannot be constructed
* @return Generator|FixedSizeCollection[]
*/
public function iterateFixedSizeCollections($collectionSize)
{
return $this->expandToFixedSizeCollection($collectionSize)->iterateCollections();
}
}